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In the 1940 USA census 50% of houses reported having indoor plumbing.

• mlyle 3y ago
  The issue here is defining what indoor plumbing is. It was a small majority in 1940 if you include heated water, a bath, and a flush toilet exclusive to that dwelling unit. If you include toilets alone and apartments with shared toilet facilities, the majority was reached a bit earlier-- around 1930, meaning that I judged indoor plumbing was rapidly becoming commonplace in the late 20s. In 1923, a huge chunk of households still used kerosene lamps as a primary means of lighting (it was a decent percentage in 1940, even).
  • jvm___ 3y ago
    Agreed, but they didn't ask the indoor plumbing question in the earlier censuses because it wasn't worth asking.